SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cb29fd6082ee1981b07e48020987bd37170a1d258fde5b9cc0c4cab7650ec58' 
  AND token = 'NZi9oUlemuj2yrS6gR0L8dN713xUeVQ8HRmX1Ys+h9U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}